Many circuit breakers are equipped to detect ground faults in addition to overcurrents. National Electrical Code Regulations require that the ground fault protection capabilities of circuit breakers must be tested when the circuit breakers are installed. After breaker installation, the ground fault detection system is subsequently inspected during regular periodic maintenance of the breaker.
In the prior art, testing the circuit breaker ground fault detection system required that the circuit breaker power conductors be disconnected and a high current source be temporarily hooked to one of the phase conductors to inject a simulated ground fault current through that phase. An alternate testing method requires that a testing panel or monitoring panel be placed in or near the circuit breaker enclosure, occupying valuable space.
There is a need for a circuit breaker having the capability to test the performance of its ground fault protection system with minimal additional equipment, time and expense.